NGHIÊN CỨU XÁC ĐỊNH LƯỢNG VẾT CADIMI VÀ KẼM TRONG NƯỚC TỰ NHIÊN BẰNG PHƯƠNG PHÁP VON-AMPE HÒA TAN ANOT XUNG VI PHÂN SỬ DỤNG ĐIỆN CỰC MÀNG BISMUT IN SITU

Tóm tắt

Heavy metal pollution (HgII, PbII, CdII
, NiII and ZnII) has become one of the most critical environmental
problems today. Bismuth film electrode prepared in situ on glassy carbon disk surface (abbreviated to
BiFE in situ) was used as working electorode for Differential pulse Anodic Stripping Voltammetry (DPASV) for the determination of cadmium (Cd) and zinc (Zn) in acetate buffer (pH  5). The influence of
the factors on Cd and Zn stripping peak curent (Ip) such as: BiIII concentration, pH, deposition potential
and deposition time, the electrode rotating speed, interferents… were investigated. At the deposition
potential of -1400 mV, the deposition time of 120s and other appropriate experimental conditions, the
method gained high sensitivity (0.224 ± 0.021; 0.094 ± 0.023 μA/ppb for Cd and Zn, respectively), good
reproducibility of the Ip: RSD = 1.7% and 2.6% (n  8) for Cd and Zn, respectively, low detection limit
(3) (corresponding to Cd and Zn are 1.19 ppb and 1.62 ppb); linear correlation bewteen the Ip and
the metal concentration was good in the range of 5 ÷ 60 ppb (R ≥ 0.999).